Rhyme and Amelia Sachs' latest case: catching a terrifying killer targeting couples...The happiest time of their lives - will be their last.William and Anna went to collect her engagement ring.1.5 carat, almost flawless.But the Promisor had other ideas for their future...Their murder - and that of the diamond cutter they were visiting - is only the first of a series of macabre attacks. Someone is targeting couples just as they start their lives together. Lincoln Rhyme and Amelia Sachs, newly married themselves, are on the hunt.But the killer is hunting down any witnesses who can help them. He has promised one thing: to destroy. Rhyme and Sachs will have to use all their own skills and determination to break his vow.